The invention relates to rotor blades made of fibre-reinforced synthetic resins, particularly rotor blades for wind turbines, and to a method of making such blades.
Rotor blades made of fibre-reinforced synthetic resins are usually made up of two rotor blade shells which are laminated in a negative mould by the hand lay-up moulding process. In keeping with the size of the blades, spar elements are fitted and are divided in the plane in which the two rotor blade shells are divided. Such spars may be metal constructions. It is also known to fill the blade shells at least partly with a foam plastic, which is ground smooth in the plane in which the blade shells are divided. The shells thus structured are joined together by adhesion (DE-26 11 235 A1; DE-30 14 347 A1). Rotor blades constructed in this way are on the one hand expensive to produce; and in addition the internal adhesive bonds joining the two rotor blade shells are difficult to check.
Another known rotor blade has a separate blade root with a shell of fibre-reinforced synthetic resin supported by a foam core. The foam core comprises blocks of foam plastic assembled from individual blocks. The root of the rotor blade has an internal cross-binding wound on an arbor which can be fixed in a winding machine; the foam plastic blocks are adhesively bonded to the cross-binding and form a supporting core for a rotor blade spar. Laminates made of unidirectional fibres extending longitudinally of the core are applied to the core in its longitudinal direction. A cross-binding applied in the winding process is provided over the fibre laminate. Foam plastic filling pieces are adhesively bonded to the spar thus structured, and form the front and rear edges of the core of the blade profile. The blade shell is put over it as a cross-binding (DE 31 14 567 A1, U.S. Pat. No. 4,494,910). In the manufacturing process the core is drawn out of the rotor blade when the rotor blade shell has been applied and cured; the core is required during manufacture in order to prevent the rotor blade from being deformed in the winding machine.